(1) Field of the Invention
The present invention relates generally to accounting systems and/or enterprise resource planning (ERP) systems. This invention more particularly relates to a sensor based accounting system for providing real-time, activity based accounting for both unit and plant wide operations in a manufacturing plant.
(2) Background Information
Conventional cost accounting systems are typically inadequate as decision support systems or as a tool for the measurement and/or analysis of manufacturing performance. Most conventional cost accounting systems were designed as fiduciary reporting systems, which typically require monthly and/or quarterly reporting, rather than as decision control systems, which typically require real-time and daily feedback. Therefore, the information collected and reported does not tend to support minute-to-minute and/or day-to-day operational activities. Furthermore, the resolution of a conventional cost accounting system tends to be limited to plant level analysis. For example, a conventional cost accounting system records the total number or amount of product(s) made in a given unit of time (e.g., monthly) and divides that number or amount by the total costs (e.g., total energy consumption plus the total material costs plus fixed overhead costs) to arrive at a price per unit or price per unit volume. It therefore tends to be difficult to obtain accurate economic information on a unit operation or plant area level. These limitations tend to be acutely realized during cost benefit analysis of various process improvement activities. Senior management generally looks to a finance and/or accounting function for confirmation (especially as it relates to costs) of process improvements. Unfortunately, as described above, conventional accounting systems lack the information required (both at a unit operation level and temporally) to provide confirmation.
The limitations of conventional accounting systems have been addressed in part by Ebling, et al., in U.S. Pat. No. 4,864,507 entitled “Method and Apparatus for Process Manufacture Control”, which is hereinafter referred to as the Ebling patent and which is fully incorporated by reference herein. The Ebling patent discloses a digital data processing apparatus for manufacturing process control having a production-modeling element for generating and storing a production model representative of various manufacturing relations. The production models may be configured to define the significant sub-plant components, such as the unit operations and plant areas, and to provide accounting information by these components. MARCAM® Corporation (Needham, Mass.) has successfully marketed this approach in both its PRISM® and PROTEAN® software packages, which are widely considered to be an improvement over conventional accounting systems, particularly for relatively complex operations, such as a specialty chemical plant in which a wide variety of resources are consumed in the production of a broad line of products, and/or wherein complex interrelationships exist between various unit operations. Nevertheless, despite its advantages and relatively successful commercial sales over the past decade, this approach remains limited in that it typically requires plant level costs, such as utilities, to be allocated (based on an arbitrary mechanism to the predetermined production model as described hereinabove) to each sub-plant component. This approach tends to limit the usefulness of such accounting systems since at the sub-plant level it only provides an estimate (based on the production model) of the actual accounting information. This approach is further limited as a decision support system (e.g., for critically evaluating process improvement measures) since the estimates tend to reinforce the production model assumptions rather than providing independently measured accounting data.
An alternate approach has been disclosed by Beaverstock, et al., in U.S. Pat. No. 5,134,574, entitled “Performance Control Apparatus and Method in a Processing Plant”, which is hereinafter referred to as the Beaverstock patent and which is fully incorporated by reference herein. The approach of the Beaverstock patent is advantageous in that it discloses a sensor-based control apparatus for providing near real-time indication of the performance of plant operations. These dynamic performance measures (DPMs) are typically engineering measurements such as quality, yield, downtime, production volume, and/or production cost and may further be used to supplement conventional process control methodologies. Nevertheless, despite this advancement, the apparatus described in the Beaverstock patent tends to be limited in that it may be essentially thought of as an engineering tool for optimizing manufacturing processes. As such it does not provide for even the rudimentary accounting requirements of a plant, such as an accounting of profit and loss (at either a plant or sub-plant level). Furthermore, and partly as a result of the above, the dynamic performance measures (particularly those expressed as costs) tend to lack credibility with senior management and those in the accounting and/or financial functional areas of a business.
Therefore, there exists a need for an accounting system that overcomes the limitations of the systems described hereinabove and that provides near real time accounting measures at both plant and sub-plant (e.g., unit operations) levels and for near real time decision support for both the engineering and accounting functions of a manufacturing plant.